Effectiveness of Moist Heat for Decontaminating Medical and Personal Protective Equipment

Posted: Jul 29, 2020

Moist Heat is Effective for Decontaminating Medical and Personal Protective Equipment

Medical and Personal Protective Equipment (PPE) has been a topic on the minds of many as of late. Medical staff are no strangers to the use of masks and gloves in their daily life, but PPE has slowly but surely become required wear for anybody entering the public sphere. However, this increased use of PPE, namely the N95 respirator, has led to a shortage for the people to whom they are most critical: medical staff and workers. Decontamination and reuse of these respirators will help alleviate the shortage. Moist heat has been shown to be an effective method of decontamination that requires a relatively short period of time. In an independent study, moist heat decontamination procedures resulted in the H1N1 virus counts too low to detect.

Decontamination is achieved by placing an object in an environment with heated air and humidity. The CDC recommends 60°C with 80% relative humidity for a duration of 15 to 30 minutes. Although the surgical N95 masks are intended to be single-use, they have been tested to show that most models are able to withstand at least 3 decontamination cycles of 30 min at 65°C to 80°C and a high relative humidity before breaking down and becoming unusable. 3M has done their own testing on the N95 respirators they produce. While they do not recommend reusing the N95s, they have confirmed that if done properly, moist heat decontamination does not affect the efficacy of the filters.


Environmental chambers have been in use for many years for all types of product testing including temperature, humidity, altitude, and vacuum. This makes them highly efficient for use in moist heat decontamination. Humidity is the key factor in decontaminating surgical N95 respirators at temperatures the components can withstand without losing their effectiveness. Moisture allows the heat to penetrate much more efficiently than dry air alone. In the case of the N95 respirator, the higher temperatures required for dry heat decontamination cause the masks to break down much quicker than when treated with moist heat. In this shortage, the lifespan of the N95 is critical.

Tenney Environmental designs and manufactures many models of environmental chambers that can be used for moist heat decontaminating applications. Our test chambers are available in a variety of temperature and humidity combinations and can easily be configured to meet the 60°C and 80% relative humidity that has been shown effective in decontaminating PPE. For more information on Tenney Environmental chambers visit our website at www.tenney.com. For more information like the above follow us on Facebook and LinkedIn.